Nerve locator/stimulator

ABSTRACT

A self contained, portable, disposable, self testing and self powered instrument for use in medical procedures to stimulate nerves and to determine if the tissue in question is a muscle controlling nerve, by delivering a maximum of 2 milliamperes of current through human tissue in the general area to be probed by an insertion of a probe electrode (negative) in subcutaneous tissue after an incision has been made and implanting a needle (positive electrode) anywhere in subcutaneous tissue as a ground.

United States Patent Naylor May 23, 197 2 54 NERVE LOCATOR/STIMULATOR3,128,759 4/1964 BelliS ..12s/2.1 R 3,027,891 4/1962 Fields et al.l28/2.06 R [72] Invent Richard Clearwam 1,158,473 11/1915 Floyd..128/405 [73] Assignee: Concept, Inc., St. Petersburg, Fla.

Primary ExaminerWilliam E. Kamm 22 l d. Ma 9 1 70 1 Fl 6 9AttorneyArthur H. Van Horn [21] Appl. No.: 17,457

[57] ABSTRACT [52] U.S.Cl. ..128/2.l R, 128/405 A lf contained, portabledisposable lf testing and lf [51] Int. Cl. ..A6lf 5/00 poweredinstrument f use in medical procedures to stimu- [58] Field of Search..l28/2.06 R, 2.1 R,419, 303.1, late nerves and to determine if thetissue in question is a l28/303.13, 405, 406; 324/ 53 u le controllingnerve, by delivering a maximum of 2 milliamperes of current throughhuman tissue in the general area [56] References Clted to be probed byan insertion of a probe electrode (negative) in UNITED STATES PATENTSsubcutaneous tissue after an incision has been made and implanting aneedle (positive electrode) anywhere in subcutane- 2,5 l Kalom ..l28/2.lR ous tissue as a ground 2,704,064 3/1955 Fizzell et al. ....128/2.l R3,207,151 9/1965 Takagi ..l28/2.1 R 2 Claim, 4 Drawing FiguresPATENTEUHMQ I972 3,664, 329

F|g.2 7 22 l5 l3 4| 4- -s 202 l7 l692| 1e :4 l2 5 I0 23 26 Fig. 4INVENTOR ma RICHARD NORMAN NAYLOR ATTORNEY 25 -3 QM MM NERVELOCATOR/STIMULATOR NATURE AND OBJECTS OF THE INVENTION This inventionresides in a sterile, disposable, portable and self powered, selftesting instrument for locating and stimulating motor nerves in a widerange of surgical procedures where identification of motor nerves isnecessary; e. g., long thoracic and intercostal nerves in chest surgery,hand and joint surgery, traumatic surgery and head and neck surgery. Inthe latter use, the instrument may be used to identify facial nerves orto locate the main trunk of the facial nerve, or to identify facialnerve in its Fallopian canal in radical mastoid surgery. The instrumentis convenient, economical and easy to use, and designed for self testingbefore use to insure its operability.

DRAWINGS In the drawings:

FIG. 1 illustrates the instrument and the manner of testing.

FIG. 2 is a wiring diagram of the series circuit employed in using theinstrument.

FIG. 3 is a longitudinal central section through the housing for theenergizers and shows the probe needle mount at the forward end of thehousing, the test bulb and grounding needle and current limiting meansin elevation; and

FIG. 4 shows a modified form of probe needle.

DESCRIPTION In carrying out the invention, the instrument includes acasing or housing, a self contained source of electrical energy, a bluntprobe needle mounted in one end of the housing, a test light bulb andbulb retainer carried in the opposite end of the housing, a flexibleinsulated electric conductor leading from the said opposite end of thehousing and having connection with a current limiting resistor and thegrounding needle.

More specifically, as illustrated in FIG. 3, the casing or housing 1comprises a rigid tube, preferably formed of tough polyvinyl or similarsubstance, having inturned annular retaining flanges 2 and 3 to providea container for one or more batteries or energizers 4 arranged inseries, a probe needle retainer 5, the metallic contact disc 6, a testlight bulb 7, spacing sleeve 15, and the bulb retainer 9, respectively.The blunt stainless steel probe needle is rigidly mounted in theinsulatin g retainer 5 and is firmly locked at its rear end portion in ametallic tube 11 by press fitting or crimping the two together. Theinner end of the tube 11 has electrical contact with the disc 6, whichin turn has electrical contact with the negative terminal 12 of theforwardmost of the series connected batteries 4.

The positive terminal 13 of the rear battery is in contact with aterminal 14 of the light bulb base projecting within the spacer sleeve15, formed of rigid insulating material. The bulb retainer 9 has anaxial opening 16 or duct through which the insulated conductor 17 isthreaded, one end of which is in electrical contact with the metalcasing of the bulb base as in 18, while its other end is connected withthe ground electrode or needle 19. Inturned flanges 2 and 3 of thecasing engage, respectively, the shoulders 20 and 21 of the retainers 5and 9 under the compression forces exerted by the coiled spring 22 onthe retainer 9 and forwardly through the bulb base electrode and thebatteries 4 and disc 6 and against the base of the probe assembly, tothereby maintain these elements in line contact as clearly illustratedin FIG. 3.

Needle I9 is rigidly carried in a Delrin hand gripping tube 23 having alongitudinal bore in which a suitable current limiting resistor element24 is housed, and is in series electrical contact with the conductor 17at one end and with the needle electrode 19 at its other end. Metallicsleeves 25 and 26 project from the ends of the tube 23 and at theirinner ends are in series electrical contact with the resistor element24.

Thus, it will be seen that in testing the instrument for operativeness,as illustrated in FIG. 1, where the probe needle is contacted with thesleeve 25, the resistance element is bypassed or shunted out and thefull current out ut of the battenes 4 1S utilized to energize and lightthe bul 7 as a signal that the instrument is in working order.

In normal use, as explained above, and with the ground needle 19implanted in living subcutaneous tissue, the probe needle 10 is insertedin an incision to locate and stimulate a nerve controlling a motormuscle. Where the probe needle (negative electrode) is touched toexposed nerve tissue, contraction of normally innervated muscle willoccur.

In such use, the needle 10 becomes an electrode of negative polaritywhile the ground needle is an electrode of positive polarity. Havingpreviously determined by test that the instrument is in working order,the current control resistor of proper value to deliver a maximum of 2milliamperes through the tissue being probed will be activated. It willbe noted that the test bulb will not light because of reduced currentoutput of the resistor.

In FIG. 4 is shown a modified form of probe needle which is providedwith a blunt or flat tip as indicated at 27 for exploring largersubcutaneous areas or for limiting the depth of probe on insertion in anincision.

It will be seen that by virtue of the invention, the instrument can bepresterilized as a whole, for one time use and may then be disposed of.The structure is simple, is economical to manufacture even as adisposable device, is easy to use and is self testing to insuresufficient current flowing through the probe needle to stimulate normalnerve tissue.

I claim:

1. A sterile, portable and disposable, self testing nervelocator/stimulator comprising a tubular casing, a source of directcurrent within the casing, a nerve probe needle mounted in one end ofthe casing in negative potential contact with said source, a flexibleinsulated conductor in positive potential contact at one end with saidsource, signal means in series with said conductor and said source, agrounding needle for implantation in living subcutaneous tissue, currentlimiting means serially connecting said grounding needle and theopposite end of said positive potential conductor, whereby to deliver acurrent maximum of approximately 2 milliamperes to subcutaneous tissue,in which the grounding needle is implanted, to said probe needle incontact with another area of living subcutaneous tissue, said positiveconductor having an uninsulated portion between said current limitingmeans and the said one end of said positive conductor adapted to becontacted by said probe needle to shunt out said current limiting meansand thereby energize the signal means.

2. In a sterile, disposable, single use nerve locator/stimulator, atubular casing, a source of direct current within the casing, asubcutaneous probe needle, a grounding needle independent of said probeneedle for implantation in subcutaneous tissue, a flexible insulatedconductor electrically connecting the grounding needle with the positivepotential of said current source, said probe and grounding needleselectrically coupled in series with said source for imparting negativepolarity to the probe and positive polarity to the grounding needle whensaid needles are in contact with subcutaneous tissue areas of a livingbeing, current limiting means serially connecting said grounding needleand the opposite end of said positive potential conductor, visual signalmeans in series with said conductor and said source, said positivepotential conductor having an uninsulated portion between said currentlimiting means and the said one end of said positive conductor adaptedto be contacted by said probe needle to shunt out said current limitingmeans and thereby energize the visual signal means.

1. A sterile, portable and disposable, self testing nerve locator/stimulator comprising a tubular casing, a source of direct current within the casing, a nerve probe needle mounted in one end of the casing in negative potential contact with said source, a flexible insulated conductor in positive potential contact at one end with said source, signal means in series with said conductor and said source, a grounding needle for implantation in living subcutaneous tissue, current limiting means serially connecting said grounding needle and the opposite end of said positive potential conductor, whereby to deliver a current maximum of approximately 2 milliamperes to subcutaneous tissue, in which the grounding needle is implanted, to said probe needle in contact with another area of living subcutaneous tissue, said positive conductor having an uninsulated portion between said current limiting means and the said one end of said positive conductor adapted to be contacted by said probe needle to shunt out said current limiting means and thereby energize the signal means.
 2. In a sterile, disposable, single use nerve locator/stimulator, a tubular casing, a source of direct current within the casing, a subcutaneous probe needle, a grounding needle independent of said probe needle for implantation in subcutaneous tissue, a flexible insulated conductor electrically connecting the grounding needLe with the positive potential of said current source, said probe and grounding needles electrically coupled in series with said source for imparting negative polarity to the probe and positive polarity to the grounding needle when said needles are in contact with subcutaneous tissue areas of a living being, current limiting means serially connecting said grounding needle and the opposite end of said positive potential conductor, visual signal means in series with said conductor and said source, said positive potential conductor having an uninsulated portion between said current limiting means and the said one end of said positive conductor adapted to be contacted by said probe needle to shunt out said current limiting means and thereby energize the visual signal means. 